In case of getting through a transition area during land operation, it is necessary to protect geophysical equipment such as electronic modules or nodes from tensile stress.
It is known to add a rope for joining together two points of a cable on each side of a geophysical equipment such as an electronic module or a node, so that the length of the rope is shorter than the distance between the two points along the cable and the geophysical equipment. Such method creates a diversion for tensile stress through the rope, creating a stress relief in the geophysical equipment and therefore protecting it. In case of three cables connected to a geophysical equipment, one of the cable, herein called the third cable, being connected directly or indirectly to a seismic sensor, such as a geophone, two ropes may be used for linking the third cable to respectively each of the two other cables, so as to protect the geophysical equipment.
A drawback of such a system with ropes is that it is insufficient and not reliable. Indeed, if the loop formed by the rope(s), which is quite big, is stressed for example by underwater debris, the corresponding tensile stress may then be communicated to the geophysical equipment itself, which may consequently lose its watertightness.
Furthermore, if the seismic sensor or third cable is stressed for example by underwater debris, the corresponding bending stress is communicated to the geophysical equipment itself, in particular to the watertightness zones, as this system of ropes does not resolve the problems linked to bending stress.
Another drawback is that such a system with ropes weakens or even damages the cables at the points at which the ropes are fixed, because of the tightly encirclement of the cables at these points.
Another known stress-relief device, as disclosed in U.S. Pat. No. 6,786,297, is adapted to high-performance cables and is very expensive, being manually incorporated during manufacturing of the equipment. This device, included in the equipment, is specifically manufactured for creating a diversion of tensile stress. Thus, the costs due to this device are very high for a use of only 5% of land operations in transition areas.